Nutrition and Lipids Overview
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Questions and Answers

Which of the following components are part of a nucleotide?

  • Hexose sugar
  • Pentose sugar (correct)
  • Fatty acid
  • Amino group

    • What is the primary function of RNA in cells?

  • Long-term storage of genetic information
  • Replication of DNA
  • Structural support to cells
  • Transfer of genetic code for protein synthesis (correct)

    • Which nitrogenous base is found exclusively in RNA?

  • Cytosine
  • Adenine
  • Thymine
  • Uracil (correct)

    • In RNA, the concentration of which base would match with adenine?

    <p>Uracil</p> Signup and view all the answers

    What structure characterizes RNA compared to DNA?

    <p>RNA is single-stranded</p> Signup and view all the answers

    What is the main process that breaks apart large organic molecules into smaller ones?

    <p>Hydrolysis</p> Signup and view all the answers

    Which of the following is the correct chemical formula for glucose?

    <p>C6H12O6</p> Signup and view all the answers

    What type of carbohydrates are formed by the combination of two monosaccharides?

    <p>Disaccharides</p> Signup and view all the answers

    Which of the following ratios represents the composition of carbohydrates?

    <p>1:2:1</p> Signup and view all the answers

    Which building block is associated with proteins?

    <p>Amino acids</p> Signup and view all the answers

    Which of the following carbohydrates is used primarily for energy storage in plants?

    <p>Starch</p> Signup and view all the answers

    What is the main building block of proteins?

    <p>Amino acids</p> Signup and view all the answers

    Which type of carbohydrate cannot be digested by animals?

    <p>Cellulose</p> Signup and view all the answers

    Which of the following best describes a peptide bond?

    <p>A bond formed between two amino acids</p> Signup and view all the answers

    Which group of amino acids must be obtained from the diet?

    <p>Essential amino acids</p> Signup and view all the answers

    What is a primary function of carbohydrates in the human body?

    <p>To provide energy and regulate metabolism</p> Signup and view all the answers

    What structure involves the linear arrangement of amino acids in a protein?

    <p>Primary structure</p> Signup and view all the answers

    Which of the following is true about polysaccharides?

    <p>They consist of long chains of monosaccharides.</p> Signup and view all the answers

    What type of interactions primarily determine the tertiary structure of a protein?

    <p>Non-covalent interactions</p> Signup and view all the answers

    Which of the following statements is NOT true regarding proteins?

    <p>Proteins are solely used for energy storage.</p> Signup and view all the answers

    What is a major characteristic that distinguishes lipids from carbohydrates?

    <p>Lipids are not soluble in water.</p> Signup and view all the answers

    Which of the following is an energy storage molecule that stores more energy than carbohydrates?

    <p>Lipids</p> Signup and view all the answers

    Which of the following best describes the physical state of fats at ordinary temperatures?

    <p>Solid</p> Signup and view all the answers

    What are the building blocks of lipids?

    <p>Fatty acids and glycerol</p> Signup and view all the answers

    Which type of lipid is known for providing a protective coating on plant leaves?

    <p>Waxes</p> Signup and view all the answers

    What is the primary biological function of proteins in the body?

    <p>Building and repairing tissues</p> Signup and view all the answers

    What defines the structure of phospholipids?

    <p>One fatty acid is replaced with a phosphate group and additional functional groups.</p> Signup and view all the answers

    How do phospholipids behave in terms of water solubility?

    <p>They are hydrophobic at one end and hydrophilic at the other.</p> Signup and view all the answers

    What is a common characteristic of all steroids?

    <p>They possess a common ring structure.</p> Signup and view all the answers

    Which class of lipids serves as a source of genetic information?

    <p>Nucleic acids</p> Signup and view all the answers

    What is the recommended limit for total fat intake as a percentage of total calories?

    <p>25-35%</p> Signup and view all the answers

    Which vitamins require dietary fat for absorption?

    <p>Vitamins A, D, E, and K</p> Signup and view all the answers

    Which of the following best describes the role of nucleotides in nucleic acids?

    <p>They are simple units connected in long chains.</p> Signup and view all the answers

    What is the primary component of cholesterol?

    <p>It possesses a common steroid ring structure.</p> Signup and view all the answers

    Study Notes

    Phospholipids

    • Phospholipids are modified triacylglycerols
    • One fatty acid is replaced with a phosphate group
    • Phosphate group binds to other functional groups
    • Phospholipids are amphipathic: one end is hydrophobic (fatty acid) and one end is hydrophilic (phosphate)

    Steroids

    • Steroids have a common ring structure
    • Functional groups attached to ring structure vary
    • Cholesterol is an example of a steroid
    • Cholesterol is a membrane component
    • Steroids are the basis of sterol hormones, including testosterone and estrogens

    Nutrition and Health

    • Most dietary lipids are triacylglycerols, cholesterol, and phospholipids
    • Some dietary fat is needed for absorption of fat-soluble vitamins (A, D, E, K) and carotenoids
    • Essential fatty acids are fatty acids that cannot be synthesized by the body and must be consumed in the diet

    The Fat Guidelines

    • Limit total fat intake to less than 25-35% of daily calories
    • Limit saturated fat intake to less than 7% of daily calories
    • Limit trans fat intake to less than 1% of daily calories
    • Limit cholesterol intake to less than 300 mg per day
    • Unhealthy fats should be replaced with monounsaturated and polyunsaturated fats from nuts, seeds, fish, and vegetable oils

    Nucleic Acids

    • Two types of nucleic acids:
      • Deoxyribonucleic acid (DNA)
      • Ribonucleic acid (RNA)
    • Nucleic acids are long chains of nucleotides linked by dehydration
    • Nucleic acids provide genetic information
    • Nucleic acids dictate amino acid sequence in proteins

    Hydrolysis

    • Hydrolysis is the reverse of condensation
    • Breaks apart large molecules into smaller ones
    • Breaks bonds between monomers
    • Releases energy stored in polymers during condensation

    Carbohydrates

    • Common formula (CH2O)n
    • Glucose is the most common carbohydrate
    • Functions: structural material, energy storage, and energy transport
    • Three types:
      • Monosaccharides
      • Oligosaccharides
      • Polysaccharides

    Carbohydrates: Monosaccharides and Disaccharides

    • Disaccharides are produced from two monosaccharides:
      • Sucrose (glucose + fructose) - Table Sugar
      • Lactose (glucose + galactose) - Milk Sugar
      • Maltose (glucose + glucose) - Found in Barley and Germinating Seeds
    • Polysaccharides are long chains of monosaccharides bound together

    Carbohydrates: Starch, Cellulose, Chitin, and Glycogen

    • Starch is an energy storage molecule in plants
    • Cellulose is a structural component in plants
    • Chitin is a partially derived non-sugar (nitrogen) component of insect exoskeletons
    • Glycogen is an energy storage molecule in animals

    Functions of Carbohydrates

    • Provide energy
    • Spare protein for energy
    • Prevent ketosis
    • Biological recognition processes
    • Flavor and sweeteners
    • Dietary fiber (essential for elimination of waste)

    Proteins

    • Most diverse molecules in structure and function
    • Proteins are polymers of amino acids
    • Thousands of different proteins are made from 20 amino acids

    Amino Acids

    • Building blocks of proteins
    • Contain an amine group (NH3), carboxyl group (COOH), and an R group
    • All groups attached to the same carbon atom
    • Essential amino acids must be obtained from the diet
    • Non-essential amino acids can be synthesized by the body
    • Amino acids form proteins through peptide bonds

    Peptide Bonds

    • Bond that forms between two amino acids

    Levels of Protein Structure

    • Primary Structure: Linear sequence of amino acids
    • Secondary Structure: Folded or coiled regions within a protein (e.g., alpha-helices and beta-pleated sheets)
    • Tertiary Structure: Final 3D structure of a protein resulting from non-covalent interactions between amino acids
    • Quaternary Structure: Non-covalent interactions between multiple polypeptides to form a larger protein (e.g., Hemoglobin)

    Functions of Proteins

    • Build, maintain, and repair body tissues
    • Can be used as an energy source
    • Storage
    • Enzymes (catalyze biochemical reactions)
    • Molecular instruments for gene expression
    • Antibodies (prevent disease)
    • Milk proteins (infant growth)

    Lipids

    • Composed of carbon, hydrogen, and oxygen
    • No specific ratio of C:H:O
    • Building blocks are fatty acids and glycerol
    • Energy storage molecules (store more energy than carbohydrates)
    • Heterogeneous in structure, insoluble in water, soluble in hydrophobic solvents
    • Examples: fats, oils, phospholipids, waxes, steroid hormones

    Fats and Oils

    • Fats are solid at room temperature, generally produced by animals, stored in adipose cells, cushion body organs, and insulate skin
    • Oils are liquid at room temperature, generally produced by plants, examples include peanut, soybean, and corn oil

    Waxes

    • Produced by plants and animals
    • Plant waxes coat leaves
    • Animal waxes include beeswax

    Nucleic Acids

    • DNA and RNA
    • Nucleotides have three parts:
      • Phosphate group
      • Pentose sugar (5-carbon)
      • Nitrogenous base:
        • Adenine (A)
        • Thymine (T) (DNA only)
        • Uracil (U) (RNA only)
        • Cytosine (C)

    DNA and RNA Structure

    • DNA: Double-stranded helix
    • RNA: Single-stranded helix
    • DNA stores and transmits genetic information
    • RNA transfers genetic code for protein synthesis from the nucleus to the ribosome

    DNA

    • Deoxyribonucleic acid
    • Long polymer with deoxyribose, phosphate backbone, and four bases (A, G, C, T)

    RNA

    • Ribonucleic acid
    • Shorter polymer with ribose, phosphat backbone, and four bases (A, G, C, U)

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    Lec-6,7 Biological Macromolecules Lecture Notes PDF

    Description

    Explore the essential concepts of lipids, focusing on phospholipids and steroids. Learn about their structures, functions in nutrition, and health impacts. This quiz will help reinforce your understanding of dietary fats and their guidelines.

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